Current knowledge and trends in age-related macular degeneration: genetics, epidemiology, and prevention

Automated Segmentation of Lesions Including Subretinal Hyperreflective Material in Neovascular Age-related Macular Degeneration

PURPOSE

To evaluate an automated segmentation algorithm with a convolutional neural network (CNN) to quantify and detect intraretinal fluid (IRF), subretinal fluid (SRF), pigment epithelial detachment (PED), and subretinal hyperreflective material (SHRM) through analyses of spectral-domain optical coherence tomography (SD-OCT) images from patients with neovascular age-related macular degeneration (nAMD).

DESIGN

Reliability and validity analysis of a diagnostic tool.

METHODS

We constructed a dataset including 930 B-scans from 93 eyes of 93 patients with nAMD. A CNN-based deep neural network was trained using 11 550 augmented images derived from 550 B-scans. The performance of the trained network was evaluated using a validation set including 140 B-scans and a test set of 240 B-scans. The Dice coefficient, positive predictive value (PPV), sensitivity, relative area difference (RAD), and intraclass correlation coefficient (ICC) were used to evaluate segmentation and detection performance.

RESULTS

Good agreement was observed for both segmentation and detection of lesions between the trained network and clinicians. The Dice coefficients for segmentation of IRF, SRF, SHRM, and PED were 0.78, 0.82, 0.75, and 0.80, respectively; the PPVs were 0.79, 0.80, 0.75, and 0.80, respectively; and the sensitivities were 0.77, 0.84, 0.73, and 0.81, respectively. The RADs were -4.32%, -10.29%, 4.13%, and 0.34%, respectively, and the ICCs were 0.98, 0.98, 0.97, and 0.98, respectively. All lesions were detected with high PPVs (range 0.94-0.99) and sensitivities (range 0.97-0.99).

CONCLUSIONS

A CNN-based network provides clinicians with quantitative data regarding nAMD through automatic segmentation and detection of pathologic lesions, including IRF, SRF, PED, and SHRM.

Glucosamine-Induced Autophagy through AMPK⁻mTOR Pathway Attenuates Lipofuscin-Like Autofluorescence in Human Retinal Pigment Epithelial Cells In Vitro

Age-related macular degeneration (AMD) is a vision-threatening age-associated disease. The retinal pigment epithelial (RPE) cells phagocytose and digest photoreceptor outer segment (POS). Incomplete digestion of POS leads to lipofuscin accumulation, which contributes to the pathology of the AMD. Autophagy could help reduce the amount of lipofuscin accumulation. In the present study, we evaluated the effects of glucosamine (GlcN), a natural supplement, on the induction of autophagy and POS-derived lipofuscin-like autofluorescence (LLAF) in ARPE-19 cells in vitro, and investigated the potential molecular pathway involved. Our results revealed that GlcN had no effect on phagocytosis of POS at the lower doses. GlcN treatment induced autophagy in cells. GlcN decreased the LLAF in native POS-treated cells, whereas malondialdehyde or 4-hydroxynonenal-modified POS attenuated this effect. 3-Methyladenine inhibited GlcN-induced autophagy and attenuated the effect of GlcN on the decrease of the native POS-derived LLAF. Furthermore, GlcN induced the phosphorylation of AMP-activated protein kinase (AMPK) and inhibited the phosphorylation of mammalian target of rapamycin (mTOR), whereas Compound C inhibited these effects of GlcN. Altogether, these results suggest that GlcN decreased the native POS-derived LLAF through induction of autophagy, at least in part, by the AMPK–mTOR pathway. This mechanism has potential for the preventive treatment of lipofuscin-related retinal degeneration such as AMD.

Hsp90 inhibition as a means to inhibit activation of the NLRP3 inflammasome

Once activated, the intracellular receptor NLRP3 assembles an inflammasome protein complex that facilitates the caspase-1-mediated maturation of IL-1β and IL-18. Inactive NLRP3 is guarded by a protein complex containing Hsp90. In response to stress stimuli, Hsp90 is released, and NLRP3 can be activated to promote inflammation. In this study, we blocked Hsp90 with geldanamycin and studied the fate of NLRP3 in human retinal pigment epithelial (RPE) cells. RPE cells play a central role in the development of age-related macular degeneration (AMD), a progressive eye disease causing severe vision loss in the elderly. IL-1α-primed ARPE-19 cells, human embryonal stem cell (hESC)-derived RPE cells, and primary human RPE cells were exposed to MG-132 and bafilomycin A to activate NLRP3 via the inhibition of proteasomes and autophagy, respectively. Additionally, RPE cells were treated with geldanamycin at different time points and the levels of NLRP3 and IL-1β were determined. Caspase-1 activity was measured using a commercial assay. Geldanamycin prevented the activation of the inflammasome in human RPE cells. NLRP3 released from its protective complex became degraded by autophagy or secreted from the cells. Controlled destruction of NLRP3 is a potential way to regulate the inflammation associated with chronic diseases, such as AMD.

Age-Related Macular Degeneration: New Paradigms for Treatment and Management of AMD

Age-related macular degeneration (AMD) is a well-characterized and extensively studied disease. It is currently considered the leading cause of visual disability among patients over 60 years. The hallmark of early AMD is the formation of drusen, pigmentary changes at the macula, and mild to moderate vision loss. There are two forms of AMD: the “dry” and the “wet” form that is less frequent but is responsible for 90% of acute blindness due to AMD. Risk factors have been associated with AMD progression, and they are taking relevance to understand how AMD develops: (1) advanced age and the exposition to environmental factors inducing high levels of oxidative stress damaging the macula and (2) this damage, which causes inflammation inducing a vicious cycle, altogether causing central vision loss. There is neither a cure nor treatment to prevent AMD. However, there are some treatments available for the wet form of AMD. This article will review some molecular and cellular mechanisms associated with the onset of AMD focusing on feasible treatments for each related factor in the development of this pathology such as vascular endothelial growth factor, oxidative stress, failure of the clearance of proteins and organelles, and glial cell dysfunction in AMD.

Spontaneous and training-induced cortical plasticity in MD patients: Hints from lateral masking

Macular degeneration (MD) affects central vision and represents the leading cause of visual diseases in elderly population worldwide. As a consequence of central vision loss, MD patients develop a preferred retinal locus (PRL), an eccentric fixation point that replaces the fovea. Here, our aim was to determine whether and to what extent spontaneous plasticity takes place in the cortical regions formerly responding to central vision and whether a visual training based on perceptual learning (PL) can boost this plasticity within the PRL area. Spontaneous and PL-induced cortical plasticity were characterized by using lateral masking, a contrast sensitivity modulation induced by collinear flankers. This configuration is known to be sensitive to neural plasticity and underlies several rehabilitation trainings. Results in a group of 4 MD patients showed that collinear facilitation was similar to what observed in age- and eccentricity-matched controls. However, MD patients exhibited significantly reduced collinear inhibition, a sign of neural plasticity, consistent with the hypothesis of partial cortical reorganization. Three AMD patients from the same group showed a further reduction of inhibition after training, but not controls. This result suggests that PL might further boost neural plasticity, opening promising perspectives for the development of rehabilitation protocols for MD patients.

The Antibiotic-free pFAR4 Vector Paired with the Sleeping Beauty Transposon System Mediates Efficient Transgene Delivery in Human Cells

The anti-angiogenic and neurogenic pigment epithelium-derived factor (PEDF) demonstrated a potency to control choroidal neovascularization in age-related macular degeneration (AMD) patients. The goal of the present study was the development of an efficient and safe technique to integrate, ex vivo, the PEDF gene into retinal pigment epithelial (RPE) cells for later transplantation to the subretinal space of AMD patients to allow continuous PEDF secretion in the vicinity of the affected macula. Because successful gene therapy approaches require efficient gene delivery and stable gene expression, we used the antibiotic-free pFAR4 mini-plasmid vector to deliver the hyperactive Sleeping Beauty transposon system, which mediates transgene integration into the genome of host cells. In an initial study, lipofection-mediated co-transfection of HeLa cells with the SB100X transposase gene and a reporter marker delivered by pFAR4 showed a 2-fold higher level of genetically modified cells than when using the pT2 vectors. Similarly, with the pFAR4 constructs, electroporation-mediated transfection of primary human RPE cells led to 2.4-fold higher secretion of recombinant PEDF protein, which was still maintained 8 months after transfection. Thus, our results show that the pFAR4 plasmid is a superior vector for the delivery and integration of transgenes into eukaryotic cells.

Seeing is believing: A review of apheresis therapy in the treatment of ophthalmologic disease

Apheresis procedures have a role in treatment of disparate diseases involving many different organ systems. Often the disease processes where apheresis plays a role in treatment are considered "orphan diseases"-relatively rare disease processes that lack specific pharmaceutical agents or established treatment protocols. Many of these disease processes can affect the eye with devastating results for the eyesight of these patients. The unique ability of apheresis to affect disease by modifying blood plasma and modulating disease-causing agents therein renders apheresis procedures valuable tools in the treatment of certain ophthalmologic diseases. This review comprehensively evaluates the role of apheresis in the treatment of ophthalmologic diseases of the eye and surrounding orbit including age-related macular degeneration, bilateral diffuse uveal melanocytic proliferation, paraneoplastic retinopathy, atopic keratoconjunctivitis, sympathetic ophthalmia, and endocrine-associated ophthalmopathy. Apheresis procedure parameters are provided for the apheresis practitioner based on review of the relevant literature.

Prevalence and factors associated with age-related macular degeneration in a southwestern island population of Japan: the Kumejima Study

AIMS

To evaluate the prevalence of and factors associated with age-related macular degeneration (AMD) in a rural population of southwestern Japan.

METHODS

This population-based cross-sectional study of all residents aged 40 years or older was conducted on the island of Kumejima, Okinawa, Japan. Of 4632 eligible residents, 3762 completed a comprehensive questionnaire and underwent ocular examination (participant rate, 81.2%). A non-mydriatic fundus photograph was used to grade AMD lesions according to the Wisconsin protocol. Prevalence of AMD was calculated and factors associated with AMD were identified by logistic regression.

RESULTS

Of 3068 subjects with gradable photographs, 469 had early AMD and 4 had late AMD. Age-adjusted prevalence was 13.4% for any AMD, 13.3% for early AMD and 0.09% for late AMD. In multivariate analysis, any AMD was positively associated with age (OR 1.04 per year, 95% CI 1.03 to 1.05), male sex (OR 1.42, 95% CI 1.14 to 1.75) and history of cataract surgery (OR 1.35, 95% CI 1.00 to 1.82) and was negatively associated with longer axial length (OR 0.85 per millimetre, 95% CI 0.74 to 0.96). Early AMD similarly showed significant associations with these same factors.

CONCLUSIONS

Prevalence of early or late AMD in a southwestern island population of Japan was 13.4% or 0.09%. Our data suggest relatively high prevalence for early AMD and low prevalence for late AMD in this sample of rural Japanese population. Significant factors associated with any or early AMD were mostly similar to that of previous studies.

Association of Apolipoprotein E Polymorphisms with Age-related Macular Degeneration Subtypes: An Updated Systematic Review and Meta-analysis

BACKGROUND AND AIMS

Age-related macular degeneration (AMD) is the worldwide leading cause of blindness among the elderly, especially in developed countries. The possible association between apolipoprotein E (ApoE) polymorphism (ε2, ε3, ε4) and AMD has been extensively investigated with conflicting results, especially when specifying different clinical phenotypes of AMD. Herein, we conducted a meta-analysis by integrating several recent large-sample studies to verify the effect of ApoE polymorphisms on AMD subtypes.

METHODS

The retrieve for targeted literature was conducted based on the PubMed, Embase, Cochrane library, and Web of Science. Summary odds ratio (OR) and its 95% confidence intervals (CIs) were used for estimation of risk. The p-value was adjusted due to the multiple comparison.

RESULTS

A total of 12 studies included in the final summary analysis, including 13842 cases and 38647 controls. ApoE ε4 carrier was inversely associated with early stage AMD (OR = 0.889, 95% CI = 0.82-0.97), geographic atrophy (OR = 0.594, 95% CI = 0.43-0.83) and neovascular AMD (OR = 0.670, 95% CI = 0.58-0.76). Stratification analysis by ethnicity revealed that the ApoE ε4 carriers was associated with neovascular AMD in both Caucasians (OR = 0.62, 95% CI = 0.47-0.83) and East Asians (OR = 0.68, 95% CI = 0.58-0.79). A significant association of ApoE ε2 carriers was only found with early AMD in Black and East Asian population, however small samples and limited studies restrict its generalization.

CONCLUSION

Our meta-analysis revealed a significantly protective role of ε4 on each subtypes of AMD, but no supportive evidence of the association of ε2 with AMD. Thus, further studies with larger samples are needed to understand the precise role of ε2 on AMD susceptibility.

Diseases and Molecular Diagnostics: A Step Closer to Precision Medicine

The current advent of molecular technologies together with a multidisciplinary interplay of several fields led to the development of genomics, which concentrates on the detection of pathogenic events at the genome level. The structural and functional genomics approaches have now pinpointed the technical challenge in the exploration of disease-related genes and the recognition of their structural alterations or elucidation of gene function. Various promising technologies and diagnostic applications of structural genomics are currently preparing a large database of disease-genes, genetic alterations etc., by mutation scanning and DNA chip technology. Further the functional genomics also exploring the expression genetics (hybridization-, PCR- and sequence-based technologies), two-hybrid technology, next generation sequencing with Bioinformatics and computational biology. Advances in microarray “chip” technology as microarrays have allowed the parallel analysis of gene expression patterns of thousands of genes simultaneously. Sequence information collected from the genomes of many individuals is leading to the rapid discovery of single nucleotide polymorphisms or SNPs. Further advances of genetic engineering have also revolutionized immunoassay biotechnology via engineering of antibody-encoding genes and the phage display technology. The Biotechnology plays an important role in the development of diagnostic assays in response to an outbreak or critical disease response need. However, there is also need to pinpoint various obstacles and issues related to the commercialization and widespread dispersal of genetic knowledge derived from the exploitation of the biotechnology industry and the development and marketing of diagnostic services. Implementation of genetic criteria for patient selection and individual assessment of the risks and benefits of treatment emerges as a major challenge to the pharmaceutical industry. Thus this field is revolutionizing current era and further it may open new vistas in the field of disease management.

Pesticide Use and Age-Related Macular Degeneration in the Agricultural Health Study

BACKGROUND

Age-related macular degeneration (AMD) is a leading cause of blindness in developed countries. Few studies have investigated its relationship to environmental neurotoxicants. In previous cross-sectional studies, we found an association between pesticide use and self-reported retinal degeneration.

OBJECTIVE

We evaluated the association of pesticide use with physician-confirmed incident AMD.

METHODS

The Agricultural Health Study (AHS) is a prospective cohort of pesticide applicators and their spouses enrolled from 1993-1997 in Iowa and North Carolina. Cohort members reported lifetime use of 50 specific pesticides at enrollment. Self-reports of incident AMD during follow-up through 2007 were confirmed by reports from participants' physicians and by independent evaluation of retinal photographs provided by the physicians. Confirmed cases (n=161) were compared with AHS cohort members without AMD (n=39,108). We estimated odds ratios (ORs) and 95% confidence intervals (CIs) by logistic regression with adjustment for age, gender, and smoking.

RESULTS

AMD was associated with ever use of organochlorine [OR=2.7 (95% CI: 1.8, 4.0)] and organophosphate [OR=2.0 (95% CI: 1.3, 3.0)] insecticides and phenoxyacetate herbicides [OR=1.9 (95% CI: 1.2, 2.8)]. Specific pesticides consistently associated with AMD included chlordane, dichlorodiphenyltrichloroethane (DDT), malathion, and captan; others with notable but slightly less consistent associations were heptachlor, diazinon, phorate, 2,4,5-trichlorophenoxyacetic acid (2,4,5-T), and 2,4-dichlorophenoxyacetic acid (2,4-D). Results were similar for men and women. Some specific pesticides were associated with both early- and late-stage AMD, but others were associated with only one stage.

CONCLUSIONS

Exposures to specific pesticides may be modifiable risk factors for AMD. https://doi.org/10.1289/EHP793.

Real-time measurement of needle forces and acute pressure changes during intravitreal injections

BACKGROUND

The purpose of this study was to use a physiological pressure transducer to measure real-time, continuous pressure changes in an ex vivo study model of porcine eyes to record the amount of force needed for scleral penetration and to measure acute intraocular pressure rise during intravitreal injections.

METHODS

A pressure transducer was inserted into the anterior chamber of 30 fresh porcine eyes, and intraocular pressure was measured 2 s prior to intravitreal injection until 2 s after. A force transducer plate was used to insert various gauge needles into the vitreous cavity and the amount of force in Newtons (N) required for scleral penetration was recorded.

RESULTS

For scleral perforation, 32- and 30-gauge needles required 0.44 N and 0.45 N, significantly less than larger gauge needles (P < 0.05). Similarly, 27- and 25-gauge needles required more force than smaller gauge needles but less than 19 gauge (P < 0.05). Intraocular pressure increased an average of 64.5 mmHg during intravitreal injection. Two seconds postinjection intraocular pressure readings showed a residual intraocular pressure increase of 11.1 mmHg from pre-injection baseline.

CONCLUSION

Real-time continuous recordings of pressure reveal that an instantaneous intraocular pressure spike occurs during intravitreal injection and appears to be separate from the intraocular pressure spike that occurs during needle insertion. This pressure spike is transient and has not been captured by previous methods of intraocular pressure measurement, which rely on single time point measurements. The clinical significance of this brief intraocular pressure spike is unclear and warrants further investigation.

Stem cell-derived retinal pigment epithelium transplantation for treatment of retinal disease

Age-related macular degeneration remains the most common cause of blindness in the western world, severely comprising patients' and carers' quality of life and presenting a great cost to the healthcare system. As the disease progresses, the retinal pigmented epithelium (RPE) layer at the back of the eye degenerates, contributing to a series of events resulting in visual impairment. The easy accessibility of the eye has allowed for in-depth study of disease progression in patients, while in vivo studies have facilitated investigations into healthy and diseased RPE. Consequently, a number of research groups are examining different approaches for the replacement of RPE cells in age-related macular degeneration (AMD) patients. This chapter examines some of these initial proof-of-principle studies and goes on to review the use of pluripotent stem cells as a source for RPE replacement in a number of current AMD clinical trials. Finally, we consider just some of the regulatory and manufacturing challenges presented in taking a promising AMD treatment from the research bench into clinical trials in patients, and how to mitigate potential risks early in process development.

Going non-viral: the Sleeping Beauty transposon system breaks on through to the clinical side

Molecular medicine has entered a high-tech age that provides curative treatments of complex genetic diseases through genetically engineered cellular medicinal products. Their clinical implementation requires the ability to stably integrate genetic information through gene transfer vectors in a safe, effective and economically viable manner. The latest generation of Sleeping Beauty (SB) transposon vectors fulfills these requirements, and may overcome limitations associated with viral gene transfer vectors and transient non-viral gene delivery approaches that are prevalent in ongoing pre-clinical and translational research. The SB system enables high-level stable gene transfer and sustained transgene expression in multiple primary human somatic cell types, thereby representing a highly attractive gene transfer strategy for clinical use. Here we review several recent refinements of the system, including the development of optimized transposons and hyperactive SB variants, the vectorization of transposase and transposon as mRNA and DNA minicircles (MCs) to enhance performance and facilitate vector production, as well as a detailed understanding of SB's genomic integration and biosafety features. This review also provides a perspective on the regulatory framework for clinical trials of gene delivery with SB, and illustrates the path to successful clinical implementation by using, as examples, gene therapy for age-related macular degeneration (AMD) and the engineering of chimeric antigen receptor (CAR)-modified T cells in cancer immunotherapy.

OCT Angiography: An Upcoming Non-invasive Tool for Diagnosis of Age-related Macular Degeneration

PURPOSE

To review the most recent findings, characteristics, faults and future perspectives of optical coherence tomography angiography (OCTA) in age-related macular degeneration (AMD).

RECENT FINDINGS

In dry AMD, OCTA is useful on the evaluation of choriocapillaris perfusion and detection of naïve quiescent non-exudative choroidal neovascularization (CNV). In wet AMD, OCTA can provide detailed anatomic and morphologic information of CNVs, which may help to understand why and how they develop and become active. In other hand, the many artifacts present in OCTA images may lead to misinterpretation and misdiagnosis.

SUMMARY

OCTA is a still developing technology that is able to provide a large amount of anatomic, functional and morphologic information in macular diseases and, particularly, AMD. As the technology evolves, the need of dye-based modalities tends to decrease.

Engineering of PEDF-Expressing Primary Pigment Epithelial Cells by the SB Transposon System Delivered by pFAR4 Plasmids

Neovascular age-related macular degeneration (nvAMD) is characterized by choroidal blood vessels growing into the subretinal space, leading to retinal pigment epithelial (RPE) cell degeneration and vision loss. Vessel growth results from an imbalance of pro-angiogenic (e.g., vascular endothelial growth factor [VEGF]) and anti-angiogenic factors (e.g., pigment epithelium-derived factor [PEDF]). Current treatment using intravitreal injections of anti-VEGF antibodies improves vision in about 30% of patients but may be accompanied by side effects and non-compliance. To avoid the difficulties posed by frequent intravitreal injections, we have proposed the transplantation of pigment epithelial cells modified to overexpress human PEDF. Stable transgene integration and expression is ensured by the hyperactive Sleeping Beauty transposon system delivered by pFAR4 miniplasmids, which have a backbone free of antibiotic resistance markers. We demonstrated efficient expression of the PEDF gene and an optimized PEDF cDNA sequence in as few as 5 × 10³ primary cells. At 3 weeks post-transfection, PEDF secretion was significantly elevated and long-term follow-up indicated a more stable secretion by cells transfected with the optimized PEDF transgene. Analysis of transgene insertion sites in human RPE cells showed an almost random genomic distribution. The results represent an important contribution toward a clinical trial aiming at a non-viral gene therapy of nvAMD.

Lutein and Zeaxanthin-Food Sources, Bioavailability and Dietary Variety in Age-Related Macular Degeneration Protection

Lutein and zeaxanthin (L/Z) are the predominant carotenoids which accumulate in the retina of the eye. The impact of L/Z intake on the risk and progression of age-related macular degeneration (AMD), a leading cause of blindness in the developed world, has been investigated in cohort studies and clinical trials. The aims of this review were to critically examine the literature and evaluate the current evidence relating to L/Z intake and AMD, and describe important food sources and factors that increase the bioavailability of L/Z, to inform dietary models. Cohort studies generally assessed L/Z from dietary sources, while clinical trials focused on providing L/Z as a supplement. Important considerations to take into account in relation to dietary L/Z include: nutrient-rich sources of L/Z, cooking methods, diet variety and the use of healthy fats. Dietary models include examples of how suggested effective levels of L/Z can be achieved through diet alone, with values of 5 mg and 10 mg per day described. These diet models depict a variety of food sources, not only from dark green leafy vegetables, but also include pistachio nuts and other highly bioavailable sources of L/Z such as eggs. This review and the diet models outlined provide information about the importance of diet variety among people at high risk of AMD or with early signs and symptoms of AMD.

Hesperetin protects against H2O2-triggered oxidative damage via upregulation of the Keap1-Nrf2/HO-1 signal pathway in ARPE-19 cells

Age-related macular degeneration (AMD) is an irreversible vision loss disease that primarily results from oxidative stress that causes oxidative damage to the retinal pigment epithelial (RPE) cells. Hesperetin (Hesp) is a common flavanone glycoside compound that has been demonstrated to exhibit a variety of biological and pharmacological properties that include anti-inflammatory and antioxidant properties. The aim of this study is to explore the ability of Hesp to attenuate oxidative damage in hydrogen peroxide (H₂O₂)-stimulated ARPE-19 cells. The results indicated that Hesp treatment not only increased cell survival but also decreased reactive oxygen species (ROS) generation, whereas these roles were effectively enhanced the superoxide dismutase (SOD) and glutathione (GSH) levels, and reduced malondialdehyde (MDA) formation. Importantly, the level of heme oxygenase-1 (HO-1) expression was increased by Hesp exposure, which resulted in a decrease after the transfection of cells with Nrf2-siRNA. Additionally, further results revealed that Hesp treatment significantly elevated Keap-1 protein expression, Nrf2 nuclear translocation and ARE activities. These observations indicated that Hesp treatment effectively protected against H₂O₂-induced oxidative damage in ARPE-19 cells by inhibiting cell apoptosis, ROS overproduction and MDA formation as well as enhancing the SOD and GSH levels. The underlying mechanisms may be related to the activation of the Keap1-Nrf2/HO-1 signal pathway, which may provide biological evidence to further encourage the investigation of the protective effect of Hesp in AMD disease.

StereoTactic radiotherapy for wet Age-Related macular degeneration (STAR): study protocol for a randomised controlled clinical trial

Background

The standard of care for neovascular age-related macular degeneration (nAMD) involves ongoing intravitreal injections of anti-angiogenic drugs targeting vascular endothelial growth factor (VEGF). The most commonly used anti-VEGF drugs are ranibizumab, bevacizumab and aflibercept. The main objective of the STAR trial is to determine if stereotactic radiotherapy can reduce the number of anti-VEGF injections that patients with nAMD require.

Methods/design

STAR is a multicentre, double-masked, randomised, sham-controlled clinical trial. It evaluates a new device (manufactured by Oraya, Newark, CA, USA) designed to deliver stereotactic radiotherapy (SRT) to nAMD lesions. The trial enrols participants with chronic, active nAMD. Participants receive a single SRT treatment (16 Gy or sham) with a concomitant baseline intravitreal injection of 0.5 mg ranibizumab. Thereafter, they attend every month for 24 months, and ranibizumab is administered at the visit if retreatment criteria are met. The primary outcome is the number of pro re nata ranibizumab injections during the first 24 months. Secondary outcomes include visual acuity, lesion morphology, quality of life and safety. Additional visits occur at 36 and 48 months to inspect for radiation retinopathy.

The target sample size of 411 participants (randomised 2:1 in favour of radiation) is designed to detect a reduction of 2.5 injections against ranibizumab monotherapy, at 90% power, and a significance level (alpha) of 0.025 (one-sided two-sample t test). This gives 97% power to detect non-inferiority of visual acuity at a five-letter margin. The primary analyses will be by intention to treat.

Discussion

The safety and efficacy outcomes will help determine the role of SRT in the management of chronic, active nAMD.

Trial registration

International Standard Randomised Controlled Trial Number: ISRCTN12884465. Registered on 28 November 2014.

ClinicalTrials.gov: NCT02243878. Registered on 17 September 2014.

Constitutive Association of Tie1 and Tie2 with Endothelial Integrins is Functionally Modulated by Angiopoietin-1 and Fibronectin

Functional cross-talk between Tie2 and Integrin signaling pathways is essential to coordinate endothelial cell adhesion and migration in response to the extracellular matrix, yet the mechanisms behind this phenomenon are unclear. Here, we examine the possibility that receptor cross-talk is driven through uncharacterized Tie-integrin interactions on the endothelial surface. Using a live cell FRET-based proximity assay, we monitor Tie-integrin receptor recognition and demonstrate that both Tie1 and Tie2 readily associate with integrins α₅ß₁ and α_Vß₃ through their respective ectodomains. Although not required, Tie2-integrin association is significantly enhanced in the presence of the extracellular component and integrin ligand fibronectin. In vitro binding assays with purified components reveal that Tie-integrin recognition is direct, and further demonstrate that the receptor binding domain of the Tie2 ligand Ang-1, but not the receptor binding domain of Ang-2, can independently associate with α₅ß₁ or α_Vß₃. Finally, we reveal that cooperative Tie/integrin interactions selectively stimulate ERK/MAPK signaling in the presence of both Ang-1 and fibronectin, suggesting a molecular mechanism to sensitize Tie2 to extracellular matrix. We provide a mechanistic model highlighting the role of receptor localization and association in regulating distinct signaling cascades and in turn, the angiogenic switch.

[Ranibizumab and exudative age-related macular degeneration: 5-year multicentric functional and anatomical results in real-life practice]

PURPOSE

The goal of this study was to evaluate five year functional and anatomical outcomes of wet AMD patients treated with ranibizumab according to a pro re nata (PRN) regimen in real-life practice.

METHODS

A retrospective, multicentric chart review of 201 eyes of 201 patients who underwent their first ranibizumab intravitreal injection (IVT) between January 1, 2007 and December 31, 2008 was performed. Best-corrected visual acuity (BCVA), central macular thickness (CMT) on SD-OCT, number of IVT and follow-up visits were collected at baseline and during the entire follow-up period of 5 years.

RESULTS

Mean BCVA at baseline was 52.3±16.5 letters. Mean BCVA change from baseline was respectively +2.8, +2.5, +1.8, -0.6 at 1, 2, 3, 4 years of follow-up. At year 5, 43% of eyes had a stable or improved letter score (≥0 letter gain), whereas 29% declined by 15 letters or more, with an overall significant mean decline of 2.8 letters (P<0.05). No correlation was observed between final visual outcome and age, baseline BCVA, type of neovascularization, naive status, number of IVT or number of follow-up visits. On SD-OCT, mean CMT was 293±96μm at baseline and was significantly reduced compared to baseline at each year end-point (P<0.005). The mean number of IVT was 15±10.4 at year 5, with 55% of eyes still being under active treatment.

CONCLUSION

PRN ranibizumab in real-life practice improved or stabilized visual acuity over 4 years. During the 5th year, progressive decline of visual acuity was observed.

Progressing a human embryonic stem-cell-based regenerative medicine therapy towards the clinic

Since the first publication of the derivation of human embryonic stem cells in 1998, there has been hope and expectation that this technology will lead to a wave of regenerative medicine therapies with the potential to revolutionize our approach to managing certain diseases. Despite significant resources in this direction, the path to the clinic for an embryonic stem-cell-based regenerative medicine therapy has not proven straightforward, though in the past few years progress has been made. Here, with a focus upon retinal disease, we discuss the current status of the development of such therapies. We also highlight some of our own experiences of progressing a retinal pigment epithelium cell replacement therapy towards the clinic.

A Large Outbreak of Fulminant Bacterial Endophthalmitis after Intravitreal Injection of Counterfeit Bevacizumab

PURPOSE

This study reports the findings in a large series of patients with acute bacterial endophthalmitis after intravitreal injection of bevacizumab (IVB) in two eye hospitals.

METHODS

Medical records were reviewed for patients who presented with acute fulminant endophthalmitis in one or two eyes following intravitreal injection of bevacizumab from two separate batches in two eye hospitals.

RESULTS

Twenty-eight eyes of 21 patients presented with acute endophthalmitis 12-48 hours after IVB injection. Cultures from the eyes and the vials were positive for E. coli and Citrobacter, each in one of the hospitals. All patients were initially treated with topical, intravitreal, and systemic antibiotics. Twenty-four eyes underwent pars plana vitrectomy. Best corrected visual acuity (BCVA) was 1.27 ± 0.89 logMAR before IVB injecti,on which decreased to 2.80 ± 0.45 LogMAR after presentation of endophthalmitis and 2.12 ± 0.97 logMAR three months after IVB injection. Final visual acuity was found to be no light perception in four eyes.

CONCLUSIONS

This large outbreak of E.coli and Citrobacter endophthalmitis occurred after intravitreal injection of counterfeit bevacizumab. Visual outcomes were very poor.

Worsening anatomic outcomes following aflibercept for neovascular age-related macular degeneration in eyes previously well controlled with ranibizumab

Purpose

Antivascular endothelial growth factor injection is the mainstay of treating neovascular age-related macular degeneration (AMD). Previous studies have shown that switching treatment from ranibizumab to aflibercept led to an improvement in eyes with recalcitrant activity. Herein, we identify a unique subset of patients whose eyes with neovascular AMD were previously well controlled with ranibizumab injections were then worsened after being switched to aflibercept.

Methods

This is a retrospective interventional case series. Eyes with neovascular AMD, previously well controlled with monthly injections of ranibizumab, which then developed worsening of subretinal fluid after being switched to aflibercept were included.

Results

A total of 17 eyes were included. All eyes developed increased subretinal fluid when switched from ranibizumab to aflibercept. Fourteen patients were switched back to ranibizumab after a single injection of aflibercept and had subsequent rapid resolution of subretinal fluid. Three patients continued with monthly aflibercept injections for two subsequent months and demonstrated the persistence of the increased subretinal fluid until they were switched back to treatment with ranibizumab at which time the fluid resolved. No eye had persistent decline in visual acuity.

Conclusion

Switching from intravitreal ranibizumab to aflibercept in eyes with well-controlled neovascular AMD may result in worsening in a subset of patients and resolves when therapy is switched back to ranibizumab.

Self-Reported Sleep Duration in Patients with Neovascular Age-Related Macular Degeneration

PURPOSE

To examine the relationship between self-reported sleep duration and neovascular age-related macular degeneration (nAMD).

METHODS

This case-control study comprised 165 subjects (57 patients with nAMD and 108 controls). Controls were matched to cases by age and sex. Participants completed a questionnaire that included questions about sleep duration and quality. Four categories of sleep duration were established; <6 hours, 6-7 hours, 7-8 hours and >8 hours. Association of sleep duration and nAMD was assessed by logistic regression analysis. Multiple logistic regression models were performed to control for possible confounders.

RESULTS

We found a significant association between short sleep duration and nAMD (for <6 hours, odds ratio, OR, 3.29, 95% confidence interval, CI, 1.32-8.27; for 6-7 hours, OR 2.25, 95% CI 0.80-6.32; and for >8 hours, OR 1.39, 95% CI 0.53-3.73) compared with the reference category of 7-8 hours. This association remained significant after adjustment for confounders (<6 hours, OR 3.09, 95% CI 1.20-7.97). In addition, a borderline significant association was observed between self-reported very bad sleep quality and nAMD (OR 2.84, 95% CI 1.02-7.88). The highest rate of sleep medication use was found in the nAMD group (p < 0.001).

CONCLUSION

Our findings provide evidence to support an association between short sleep duration and nAMD. Considering strategies to improve sleep in these patients may prevent the negative effects of sleep deficiency.

Quality of Life in Patients Suffering from Active Exudative Age-Related Macular Degeneration: The EQUADE Study

PURPOSE

Age-related macular degeneration (AMD) is the main cause of visual loss in the elderly population. With the use of anti-vascular endothelial growth factor, the visual outcomes of exudative AMD patients have been improved. This study was aimed at assessing the quality of life (QoL) of exudative AMD patients treated with ranibizumab and at determining its drivers in a real-life setting.

METHODS

We performed a national, cross-sectional, observational survey based on questionnaires sent to members of French associations relative to AMD between December 2012 and March 2013. Patients suffering from exudative AMD with at least one intravitreal injection of ranibizumab within the last 6 months were included. Demographics, AMD characteristics, visual acuity (VA) and past and ongoing treatments were collected. The 25-item National Eye Institute Visual Function Questionnaire (NEI-VFQ-25) was self-administered. A multivariate model was used to identify QoL drivers.

RESULTS

416 questionnaires fulfilled the complete criteria for both QoL and cost analyses. The mean age of exudative AMD patients was 78.0 years and bilateral involvement was reported in 60.4%. The overall mean QoL score was 53.4. Mental health, driving and role difficulties were the most widely affected domains. After bivariate analyses, long-term illness status, worse VA and higher number of unpaid aids were associated with worse QoL, with odds ratios of 2.4, 5.2 and 11.6, respectively. The mean cost per year and per patient was 1,741 EUR. The main components of costs were aids and services and the purchase of visual equipment.

CONCLUSIONS

The main predictors of QoL in exudative AMD patients treated with ranibizumab are VA outcomes, home healthcare and social services provided to the patients.

Age-related macular degeneration: a complementopathy?

Age-related macular degeneration (AMD) is a progressive eye disease affecting many elderly individuals. It has a multifactorial pathogenesis and is associated with numerous environmental (e.g. smoking, light and nutrition) and genetic risk factors. A breakthrough in the mechanisms causing AMD is emerging; the involvement of the alternative pathway of the complement system appears to play a pivotal role. This has led to the statement that AMD is a disease caused by a hyperactive complement system, allowing the term 'complementopathy' to define it more precisely. Abundant evidence includes: the identification of drusen components as activators of complement, immunohistochemical data showing the presence of many species of the complement system in the retinal pigment epithelium-Bruch's membrane-choroidocapillary region of AMD eyes, a strong association of AMD with certain genetic complement protein variants, raised complement levels in blood from AMD patients and the preliminary successful treatments of geographic atrophy with complement factor D (FD) inhibitors. FD is the rate-limiting enzyme of the alternative complement pathway, and is produced by adipose tissue. Recent findings suggest that nutrition may play a role in controlling the level of FD in the circulation. Addressing modifiable risk factors such as smoking and nutrition may thus offer opportunities for the prevention of AMD.

The effect of normal aging and age-related macular degeneration on perceptual learning

We investigated whether perceptual learning could be used to improve peripheral word identification speed. The relationship between the magnitude of learning and age was established in normal participants to determine whether perceptual learning effects are age invariant. We then investigated whether training could lead to improvements in patients with age-related macular degeneration (AMD). Twenty-eight participants with normal vision and five participants with AMD trained on a word identification task. They were required to identify three-letter words, presented 10° from fixation. To standardize crowding across each of the letters that made up the word, words were flanked laterally by randomly chosen letters. Word identification performance was measured psychophysically using a staircase procedure. Significant improvements in peripheral word identification speed were demonstrated following training (71% ± 18%). Initial task performance was correlated with age, with older participants having poorer performance. However, older adults learned more rapidly such that, following training, they reached the same level of performance as their younger counterparts. As a function of number of trials completed, patients with AMD learned at an equivalent rate as age-matched participants with normal vision. Improvements in word identification speed were maintained at least 6 months after training. We have demonstrated that temporal aspects of word recognition can be improved in peripheral vision with training across a range of ages and these learned improvements are relatively enduring. However, training targeted at other bottlenecks to peripheral reading ability, such as visual crowding, may need to be incorporated to optimize this approach.

Acute sterile endophthalmitis following intravitreal bevacizumab: case series

Background

Since the ophthalmological community adopted the use of intravitreal bevacizumab as an accepted off-label treatment for neovascular diseases, the amount of knowledge regarding its effects and properties has been increasing continually. In the last few years, there have been an increasing number of reports about sterile intraocular inflammation and intraocular pressure elevations after intravitreal bevacizumab. In the following case series, we describe the clinical presentation and outcomes of ten consecutive cases of patients developing mild-to-severe sterile intraocular inflammation after intravitreal bevacizumab and their management.

Methods

This report presents a retrospective case series. We reviewed the medical records of ten consecutive patients from a group of 46, in whom repackaged bevacizumab in individual aliquots from two vials from the same batch were used. All surgical procedures were performed using standard sterile techniques in the operating room. At each follow-up visit, patients underwent a complete ophthalmological examination including visual acuity assessment, intraocular pressure, biomicroscopy, and posterior fundus examination.

Results

Ten patients presented sterile endophthalmitis with an onset time of 3.5±1.95 days. The clinical characteristics were mild pain, slight visual loss, conjunctival hyperemia, and various degrees of intraocular inflammation with microhypopyon. All cultures were negative. All patients were managed with topical steroids and antibiotics, except two, in whom, due to severe vitreous cells, intravitreal antibiotics were used. Three patients showed a transient elevation of intraocular pressure. Only 50% of the patients regained a visual acuity equal or better to the baseline visual acuity on file.

Conclusion

The increasing number of intravitreal injections of bevacizumab applied every day, due to its widespread acceptance, might be one reason why the number of cases of sterile endophthalmitis is rising. Fast recognition and accurate differential diagnosis is important to avoid unnecessary treatments and long-term complications. The low incidence of this event should not preclude the use of intravitreal injections in eyes that could benefit greatly from this therapy.